[SIPForum-discussion] question on PRACK

Wed May 11 22:57:47 UTC 2011

Hello all,
One of our carrier requires support for PRACK.
When the carrier sends 183 Session Progress, we send PRACK and receive 200 OK for the PRACK.
Then they again send 180 Ringing and our SBC rejects the call.
I believe we are right here to reject the call, because the carrier shouldnt be sending 180 ringing after receiving PRACK for 183 Session Progress. Please let me know.
Also if possible please point me to any rfc which says PRACK to 183 should not be followed by 180.
Thanks,Raghul
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